Fibrous insulation is typically formed by fiberizing molten material and depositing the fibers on a collecting conveyor. Typically the fibers for insulation products are mineral fibers, such as glass fibers, although some insulation products are made of organic fibers, such as polypropylene. Most fibrous insulation products contain a binder material to bond the fibers together where they contact each other, forming a lattice or network. The binder gives the insulation product resiliency for recovery after packaging, and provides stiffness and handleability so that the product can be handled and applied as needed in the insulation cavities of buildings. During manufacturing the insulation is cut into lengths to form individual insulation products, and the insulation products are packaged for shipping to customer locations.
One typical insulation product is an insulation batt, usually about 8 feet long, and generally suitable for use as wall insulation in residential dwellings, or as insulation in the attic and floor insulation cavities in buildings. The width of insulation batts designed for wall cavities is set to typical insulation cavity widths, such as about 141/2 inches or 221/2 inches for stud spacings of 16 and 24 inches, respectively. Some insulation products have a facing on one of the major surfaces. In many cases the facing acts as a vapor barrier, and in some insulation products, such as binderless products, the facing gives the product integrity for handleability. Faced insulation products are installed with the facing placed flat on the edge of the insulation cavity, typically the interior side or edge of the insulation cavity.
Insulation products where the facing is a vapor barrier are commonly used to insulate wall, floor or ceiling cavities that separate a warm interior space from a cold exterior space. The vapor barrier is usually placed to prevent moisture-laden air from the warm interior of the dwelling from entering the insulation. Otherwise, the water vapor in the warm interior air would enter the insulation material and then cool and condense within the insulation. This would result in a damp insulation product, which is incapable of performing at its designed efficiency. In warm climates it is sometimes preferable to install the vapor barrier on the exterior side of the insulation cavity to reduce the amount of vapor entering the building during the air conditioning season.
There are some insulation product requirements that call for insulation that is not vapor impermeable, but rather allows water vapor to pass through. For example, retrofit insulation products designed for adding additional insulation material on top of existing attic insulation should not have a vapor barrier. Also, insulation for wall cavities having a separate full wall vapor barrier, such as a 4.0 mil polyethylene film on the interior or warm side of the wall, do not require a vapor barrier on the insulation product itself. Further, encapsulation of fibrous glass batts for handling purposes is known. U.S. Pat. No 5,277,995 to Schelhorn et al. discloses an encapsulated batt with an encapsulation material adhered with an adhesive that can be applied in longitudinal stripes, or in patterns such as dots, or in an adhesive matrix. The Schelhorn et al. patent also discloses that an alternative method of attachment is for the adhesive layer to be an integral part of the encapsulation film, which, when softened, bonds to the fibers in the batt. U.S. Pat. No 5,733,624 to Syme et al. discloses a mineral fiber batt impregnated with a coextruded polymer layering system, and U.S. Pat. No 5,746,854 to Romes et al. discloses a method for impregnating a mineral fiber batt with a coextruded film.
Vapor barriers for insulation products are typically created with a layer of asphalt in conjunction with a kraft paper or foil facing material. The asphalt layer is applied in molten form and it is pressed against the fibrous insulation material before hardening to bond the kraft facing material to the insulation material. This asphalt and kraft paper system has the advantage of being relatively inexpensive. However, this facing system lacks flexibility because the asphalt/kraft layer is stiff, and working with the stiff asphalt/kraft facing slows down the installation of the insulation products. Also, cutting the facing without tearing the kraft paper is difficult in cool ambient temperatures because the asphalt can be brittle. Further, and the asphalt material is sticky in hot ambient temperatures, resulting in a gumming up of the cutting tool.
Even though the batts are manufactured to fit typical insulation cavities, many of the insulation cavities in buildings are of nonstandard dimensions. Window frames, door jambs, vent pipes, air ducts and electrical conduit are some of the typical obstructions that change the shape of the insulation cavity. During the process of installing the batts a significant portion of the batts must be cut to fit these non standard insulation cavities. In some dwellings up to 50 percent of the insulation cavities are nonstandard. Therefore, an important attribute of a faced building insulation product is the ease with which the facing can be cut and the ability of the facing to be placed flat on the edge of the insulation cavity after the facing has been cut. If the facing is not flat on the edge of the insulation cavity, the vapor barrier will be only partially effective. Further, insulation customers desire a smooth facing that is relatively flat on the edge of the insulation cavity.
In view of the above problems with currently available insulation products, it would be advantageous if there could be developed a faced insulation product having a facing material that can be easily cut to fit into nonstandard insulation cavities, and having a facing material that is flexible enough that it can accommodate faster installation of the cut insulation product into nonstandard insulation cavities with the facing in a flat condition at the edge of the insulation cavity.